Over the past 2 years, I have had the fortunate opportunity to represent AEIRS as a member of the Communicating Advances in Radiation Education for Shielding (CARES) Committee, working with professionals from different sectors to share diverse opinions and perspectives, discuss potential changes to clinical practice and to participate in the development of communication and educational activities regarding the discontinuation of gonadal and fetal shielding in diagnostic radiology.
Since April of 2019, there has been considerable discussion about the use of patient gonadal and fetal shielding in diagnostic x-ray imaging, prompted primarily by the publication of the position statement on this topic by the American Association of Physicists in Medicine announcing that the routine use of patient gonadal and fetal shielding, once a mainstay of patient radiation protection, may no longer be best practice for protecting our patients. Its purpose was to educate the imaging community that these fetal and gonadal shields provide no tangible benefit to patients; may compromise radiologic examinations by interfering with important patient anatomy; or may actually increase patient dose to more sensitive organs, such as the stomach and colon, when placed in the x-ray beam path and detected by an automatic exposure control system. I know Heidi Sebastian mentioned the OSRT’s response in her presentation on Friday morning and I hope I can help you all understand why there is a need to make this significant change in our practice.
From an historical perspective, the widespread practice of gonadal shielding did not really begin until the 1950’s due to concerns that radiation exposure to the gonads would cause mutations in one’s offspring. It was in 1976, that the Food and Drug Administration added a section to the Code of Federal Regulations suggesting that gonads be shielded during diagnostic radiographic examinations due to concerns about the hereditary effects to offspring. It is important to point out that this was a recommendation, it was not a requirement, and it was issued over 40 years ago. Over this time period, longitudinal research studies have found no hereditary effects in humans from radiation levels associated with diagnostic imaging. In fact, data regarding fetal dose suggest that doses of less than 100mGy demonstrate a very small to nonexistent risk to an embryo or fetus. Consequently, genetic risk estimations in human populations have concluded that there is no direct evidence of a radiation associated excess of heritable disease. It is also important to understand that the tissue weighting factors have changed significantly over the years. This is not totally new information. In 1977 the International Committee on Radiation Protection assigned the gonads a tissue weighting factor of 0.25. However, this dropped to 0.20 in 1990 and to 0.08 in 2007. Currently the red bone marrow, the breasts, the colon, and the stomach are the most sensitive organs with a tissue weighting factor of 0.12.
Additionally, there have been major changes in x-ray tube design, tube shielding requirements, improvements in generators, AEC, and imaging receptors over the past 40 years that have significantly reduced to amount of radiation required to obtain an optimized radiographic image.
Therefore, in January 2021, the National Council on Radiation Protection concluded that in most circumstances gonadal shielding use does not contribute significantly to reducing risks from exposure and may actually have the unintended consequences of increased exposure and loss of valuable diagnostic information. They NCRP now recommends that gonadal shielding not be used routinely during abdominal and pelvic radiography, and that federal, state, and local regulations and guidance should be revised to remove any actual or implied requirement for routine gonadal shielding. They do acknowledge, however, that gonadal shielding use may remain appropriate in some limited circumstances. The recommendations in this NCRP statement are limited to patient gonadal shielding during abdominal and pelvic radiography.
The most recent ARRT Radiography task inventory, content specifications, and clinical competency requirements which are effective January 1, 2022 have implemented this change. In the Safety section, genetic impact was removed. Embryonic and fetal risk were moved to the somatic effects sub-section. Under minimizing patient exposure, shielding was removed from the document. Additional detail about protective devices was added under personnel protection and ALARA.
The ASRT Radiography Curriculum revision cycle which is in process, most likely would not be implemented into educational practice until 2023, which, in turn may prompt a change in the JRCERT standards depending upon the final updated radiography curriculum.
Nina Kowalczyk, PhD, RT, (R)(QM)(CT)